Tracking technology like the leading products ATLAS, Performix are excellent and should be a consideration for any online marketer today.  Tracking technologies allow you to track any online marketing campaign from pop ups to PPC campaigns like Google Adwords.  Generally these are available on the market usualy for a minimum of £500 per month.  The way these work is, conversion code is place on a sale confirmation page, then you set your redirects up so that when your ad is seen on Google (for example), the user goes from Google’s server and is redirected very quickly to the tracking server and then back to the target page.  In order to allow that to happen, the redirects must be set up in Google to the tracking server, and the target pages must be set up in the tracking server (known as trafficking).  That way you can see which ad campaigns are making you money and which ones arent.